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As a non- native speaker of English, I often find myself struggling with the usage of the suffix -al in adjectives. For instance, what's the difference between the words "historic" and "historical", "metaphoric" and "metaphorical", etc? Are there any rules as far as this suffix is concerned?

marked as duplicate by tchrist, sumelic, Mari-Lou A, Janus Bahs Jacquet, choster Jul 21 '15 at 19:40

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There is no system in adjectives with the suffix -al. I once had a closer look at adjectives in -ic/ical. You find a variety of types.

Type: historical/historic

historical is the normal word, historic has a special meaning.

Type: geometric/geometrical

Both forms are used

Type: logic/logical

Logic is the noun, logical the adjective

Type: practical

There is only one adjective form: practical. Of the same type:impractical, theoretical, hypothetical.

This is no exhaustive study. This is only meant to show you that there is no system in this type of word formation and you have to verify each adjective in -ic/ical to see the usage.


These sites might help:

  1. http://grammarist.com/usage/historic-historical/
  2. http://grammarist.com/spelling/metaphoric-metaphorical/

Some of these types of pairs undergo differentiation whereby they develop slightly different meanings (e.g. historic/historical). Others don't (e.g. metaphoric/metaphorical).

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